Pattern control mechanism for looms



NOV. 25, 1969 c; UBBY 3,480,047

PATTERN CONTROL MECHANISM FOR LOOMS OII'LgiI'lll Filed July 31, 1967 2 Sheets-Sheet 1 CARL. F. L Y BY ATTORNEYS Nov. 25, 1969 c. F. ussv 3,480,047

PATTERN CONTROL MECHANISM FOR LOOMS Original Filed July 31, 1967 2 Sheets-Sheet K2 5 26 INVENTOR. 59 CARL F. LIBBY BY m. 2 m

ATTORNEYS 3,480,047 PATTERN CONTROL MECHANISM FOR LOOMS Carl F. Libby, Stoughton, Mass., assignor to John D.

Riordan, Hopkinton, and Gertrude C. Libby, Stoughton, Mass., trustees of the Libby Family Trust Continuation of application Ser. No. 657,329, July 31, 1967. This application Jan. 10, 1969, Ser. No. 796,273 Int. Cl. D03d 49/00, 45/10 U.S. Cl. 139-319 9 Claims ABSTRACT OF THE DISCLOSURE The harness frames or single heddles of a loom are individually operated by solenoids which are energized by circuits by which each frame is pulled to its raised or lowered position according as a photo-electric element associated with the frame is activated or deactivated. A spring for each frame tends to hold it yieldingly in a midppsition, whereby the initial half of an up or down movement of a frame during which the pull of the solenoid is weakest is assisted by the spring.

If the drive of the belt is synchronized with the weftlaying mechanism for low and moderate speeds, as it should be, the shed-changes lag somewhat when the loom is operated at high speeds. A governor is connected into the driving means for the belt and operates to advance the timing of the belt drive in accordance with the speed of operation of the loom.

This application is a continuation of Ser. No. 657,329, filed July 31, 1967, and now abandoned.

The invention relates to looms having a number of harness frames which are individually and selectively movably up and down to vary the warp shed between successive picks of the weft-laying member. Solenoids are employed to raise and lower the harness frames and may also be used to raise and lower selected individual heddles. The energization of the solenoids is controlled by electronic means including a light source, photoelectric elements arranged to be activated by light from the source, and an endless programming belt which passes between the light source and the photo-electric elements, the belt having series of apertures opposite the several photo-electrical elements and driving means synchronized with driving means for the weft-laying members to expose the several photo-electric elements to the light source at predetermined intervals for the production of desired weaving patterns. While the invention can be embodied in various kinds of looms, it is herein described and illustrated in a narrow web loom designed to operate at high speeds. A portion of such a loom sufficient to illustrate the invention is shown on the drawings, of which 4 FIGURE 1 is a perspective view of parts of a narrow web loom having a harness frame control apparatus and governor embodying the invention;

' FIGURE 2 is an elevational view, on a larger scale, of the harness frames and the solenoids for raising and lowering them;

FIGURE 3 is a fragmentary sectional view, on a larger scale, of the control means shown in FIGURE 1;

FIGURE 4 is a fragmentary elevational view of the same;

United States Patent FIGURE 5 is an elevational view of one of the solenoid brackets with its operating arm and spring; and

FIGURE 6 is a wiring diagram of the electronic means for operating one of the harness frames.

The drawings show such parts of a narrow-web loom as are required to illustrate the present invention. Such a'loom is shown in Patent No. 2,180,831, but the invention is applicable to other types and sizes of looms.

Supported by a main-frame 20 are a number of harness frames 22 and rotary solenoids K and K for rapidly raising and lowering the frames, each solenoid K having an arm 24 projecting therefrom, the free end ofthearm being secured to the top of a harness frame 22, each solenoid K being similarly connected to the lower eild of a frame 22 by an arm 26 projecting therefrom. Each frame holds a set of heddles, that is, wires each of which has a small loop through which a warp yarn passes. FIGURE 2 shows the frames 22 in an intermediate position which they all assume when the loom is not in operation. When the loom is in operation each frame is in either the raised position, the arms 24, 26 being in the positions indicated at 24A, 26A, or in the lowered position, the arms 24, 26 being as indicated at 24B, 26B. As usual in the operation of weaving one or more of the harness fraames must be raised or lowered after each pick to change the warp shed. The operation of the solenoids K and K for this purpose is controlled electronically by apparatus such as is illustrated on the drawings and is hereinafter described. During the operation of the loom, either the solenoid K or the solenoid K for each harness frame is energized, but not both at the same time. For each set of solenoids K K a photo transistor Q is mounted in line with a hole 30 and a light source 32, six such holes being shown in FIGURE 1 by way of example for the operation of six frames in the loom. A greater number of holes and photo transistors can be used as desired. Between the holes 30 and the photo transistors Q, is a screen in the form of an endless belt or strip 34 having a series of uniformly spaced holes 36 to receive teeth 38 on a roll 40 by which the belt 34 is advanced. The belt also has a series of apertures 42 opposite each hole 30 to permit light beams to strike the photo transistors when the corresponding apertures are in line with one or another of the holes 30. The roll 40 is driven from a shaft 44 which is operatively connected by means (not shown) to a power driven shaft 46 by which other moving parts of the loom are driven, the connections being such that the belt 34 is advanced one tooth-space after each pick, the warp shed thus being changed between ecah two successive picks. From the shaft 44 is also driven a fabric take-up roll 48 through reduction gearing 49.

Each of the solenoids K or K is encased in a circular bracket 50 mounted on the frame 20. As indicated in FIGURES 2 and 5, the brackets are preferably provided with peripheral vanes 52 to dissipate heat generated by the energization of the solenoids within. A wire spring 54 is provided for each solenoid arm 24 or 26. Each wire is secured near one end to the corresponding solenoid bracket 50 as at 56 and is horizontal, as indicated in FIGURE 2, when the loom is not in operation. The free end of each wire spring passes through a small hole in an ear 58 struck from each arm 24 or 26. Thus when an arm is raised or lowered from the mid position shown in FIGURE 2, such movement flexes its spring 54 which then tends to restore the arm to its mid position. The circuitry shown in FIGURE 6 is such that when an aperture 42 in the belt 34 is in line with a hole 30 so that a light beam strikes the photo transistor behind that aperture, the corresponding harness frame is pulled down to the low position. When light is cut off from a photo transistor, the corresponding harness frame is pulled up to the raised position, each such movement, down or up, tensing the springs 54. When in the operation of the loom a harness frame is raised or lowered from one extreme position to the other, the tensed springs impel the arms 24 and 26 through the first half of their movement, the force of the active solenoid being weakest at the beginning of the shifting movement of the frame. When the arms pass their mid position, the momentum of the harness frame and the increased force exerted by the energized solenoid quickly complete the shift.

In the wiring diagram illustrated in FIGURE 6, Q is a photo transistor which is arranged in line with the light source 32 and one of the holes 30 so that when an aperture 42 in the screen 34 is opposite the hole 30, a beam of light falls on the photo transistor Q and makes it electrically conductive. This draws current through the base of Q diverting current away from the base of Q so that the voltage drop across the solenoid K approaches zero and this solenoid ceases to pull upward on the harness frame attached to it.

At the same time, as there is a negligible amount of current in the solenoid K and collector of Q is at volts, the resistances of R and R operate as a voltage divider in such a manner that current is drawn through the base-emitter of Q causing the collector of Q to conduct a current through the solenoid K thus pulling the harness frame down.

When no light beam strikes the photo transistor Q no current is drawn by Q through the base of Q Q is thus cut off, and Q conducts, energizing the solenoid K to pull the harness frame up. The voltage across Q is small and the resistances R and R form a voltage divider tending to drive current through the base-emitter junction of Q against the direction of the arrow. This deenergizes the solenoid K so that it does not oppose the lifting action of the solenoid K The simultaneous energization of one of each pair of solenoids K and K and the deenergization of the other is thus brought about by electronic means Without any moving element.

For successful operation of the apparatus for moving the harness frames up and down, members having suitable characteristics should be employed. For example, the following members can be used:

Q Fairchild photo transistor FPM-100 Q 2N2428 R R ZOO ohms, 2 watts R 39 ohms, 1 watt R 560 ohms, /2 watt K K -Ledex Rotary Solenoid No. 129731-026 The foregoing is but an example of many circuits which can be used for operation of the harness frames.

The drive of the belt 34 which controls the changes of the warp shed is synchronized with the weft-laying mechanism and the loom operates well at moderate speeds but narrow web looms of the type for which this invention is designed are intended for high-speed operation. At such speeds there appears to be a slight lag between the picks and the shed changes. To remedy this difiiculty a governor is connected between the drive shaft (which is geared to the weft-laying mechanism) and the roll 40 which drives the belt 34. The action of the governor is such that at low or moderate speeds the roll 40 is in step with the drive shaft 44, but when the loom is operated at high speeds the roll 40 is slightly in the lead so that the shed changes are not late with respect to the laying of the weft.

As indicated in FIGURE 1 a governor crank 60 is mounted at the end of the drive shaft 44, the shaft being secured to the mid-point of the crank 60. Journalled in the crank near its ends are two short shafts 62, 64. At one end of the shaft 62 is fixed an arm 66 and at the other end is a pinion 68. In like manner the short shaft 64 has an arm 70 fixed on one of its ends and a pinion 72 fixed on the other end. The arms are arranged S0 that when the shaft 44 rotates and the crank 60 revolves with it, the arms 66 and 70 tend to swing outward against the pull of a tension spring 74 which extends between the mid points of the arms. The pinions 68 and 72 mesh with a gear wheel 78 which is loosely mounted on the drive shaft 44 but is rigidly connected by a tubular shaft 80 with a sprocket wheel 82 which also is loosely mounted on the drive shaft 44. The sprocket wheel 82 is connected by a chain 84 and gearing 86 to the roll 40. When the loom is in operation and the speed of rotation of the drive shaft 44 is not sufiicient to cause the arms 66 and 70 to swing outward, the shaft 44 and tubular shaft 80 rotate at the same speed. When the speed of rotation of the shaft 44 is sufficient to cause the arms 66 and 70 to swing out, the outward swing turns the pinions 68 and 72 slightly and they turn the gear wheel 78 so that while the shaft 44 and sprocket wheel 82 continue to rotate together, the sprocket is slightly in the lead with respect to the drive shaft 44 so that the shed changes occur slightly earlier than they do when the loom is operating at moderate speeds. To prevent excessive outward swing of the arms 66 and 70, a slotted limit bar 88 extends from one arm to the other, each arm having a headed pin 90 which rides in the respective slots.

I claim:

1. In a loom having warp-guiding means, mechanism for raising said means to an up position and lowering said means to a down position, said mechanism comprising solenoids each having a projecting arm the free end of which is secured to the top or bottom of said means, a light source, photo-electric elements adjacent to said light source, electrical circuits each including one of said solenoids and a corresponding photo-electric element, and a screen between said light source and said photo-electric elements, said screen having apertures therethrough and being movable to bring said apertures to and from alignment with the light source and individual photo-electric elements for the energization of the respective solenoids.

2. The combination claimed in claim 1, said warpguiding means consisting of a single heddle.

3. The combination claimed in claim 1, said warpguiding means consisting of a harness frame having a plurality of heddles.

4. The combination claimed in claim 1, and spring means mechanically connected to said warp-guiding means, said spring means tending to move said warpguiding means to a position midway between its up and down positions.

5. The combination claimed in claim 1, said screen being an endless strip of opaque material arranged with a portion thereof arranged between said light source and said photo-electric elements, and driving connections for said screen.

6. The combination claimed in claim 5', said driving connections including a drive shaft, a roll about which said screen passes and a governor connected between said drive shaft and roll, said governor being constructed and arranged to advance the roll relatively to the drive shaft, the amount of said advance depending on the rate of rotation of the drive shaft.

7. The combination claimed in claim 1, said circuit being arranged to energize one of said solenoids and deenergize the other solenoid when a light beam is striking a corresponding photo-electric element and to deenergize the first said solenoid and energize said other solenoid when the light beam is cut from said photo-electric element.

8. The combination claimed in claim 7, said circuit including transistors and no moving element.

9. In a loom having warp-guiding means, mechanism for raising said means to an up position and lowering said means to a down position, said mechanism comprising two solenoids and at least one arm operatively connecting said solenoids to said wrap-guiding means and rockable by said solenoids to move the warp-guiding means to the up and down positions, spring means tending to maintain said arm in a mid position in which said guiding means is between its up and down positions, a light source, photo-electric elements adjacent to said light source, electrical circuits each including one of said solenoids and a corresponding photo-electric element, and a screen between said light source and said photo-electric elements, said screen having apertures therethrough and being movable to bring apertures to and from alignment with the light source and individual photo-electric elements for the energization of the respective solenoids.

References Cited UNITED STATES PATENTS 1,822,306 9/1931 Nakanishi 139319 2,136,076 11/1938 Fisher et al 139-55 2,136,090 11/1938 Tandler et a1. 139-55 2,609,840 9/1952 Murphy 13955 3,060,975 10/1962 Pfarrwaller 139317 3,192,957 7/1965 ONeill 13955 FOREIGN PATENTS 117,001 1/1958 U.S.S.R.

JAMES KEE CHI, Primary Examiner 

